Compressed gas-operated propelling mechanism



Dec. 31, 1957 R. s. MARTIN coMPREssED GAS-OPERATE'D PROPELLING MECHANISMFiled Feb. 28, 1955 2 Sheets-Sheet 1 Dec. 31, 1957 R. s. MARTIN2,818,056

COMPRESSED GAS-OPERATED PROPELLING MECHANISM Filed Feb. 28, 1955 El o gl10 104 2a 24 5 11 a2 114 2 Sheets-Sheet 2 4 56 f i 3 E? f 2404/?9/415/2f )f1/6) 06 j `.IN1/EN TOR. af/er 6.1444671 United States PatentCOMPRESSED GAS-PERATED PROPELLING NECHANISM Robert S. Martin, LosAngeles, Calif.

Application February 28, 1955, Serial No. 490,778

4 Claims. (Cl. 124-11) This invention relates generally to a compressedgas operated propelling mechanism and will be particularly described andillustrated herein as embodied in a weapon for firing projectiles suchas -a pistol, although it is to be understood that the invention is notlimited to such uses. For example it may be applicable to machines forperiodically propelling any of a wide variety of objects in apredetermined direction, as will be seen as the description progresses.

This invention is an improvement over that shown in my United StatesPatent No. 2,688,321.

in the presently preferred embodiment herein shown and described, apistol includes a frame having a grip portion provided with a cavity forhousing a container of pressure gas such as, for example, a cartridge ofcaroon dioxide. The frame also includes a bore and means for supportinga tubular barrel slidable relative to the frame. Spaced relativelymovable bushing members or sleeves hermetically seal with the bore andbarrel thereby forming a variable volume compression chamber. Pressuregas from the container is continuously fed into the chamber, and gasfrom the chamber is periodically admitted into the barrel for firingduring the cycle of operation through one or more ports formed in thebarrel wall. A feeding magazine containing a plurality of projectiles orpellets projects into the barrel from the rear and is adapted to releaseone such pellet at a predetermined point in the cycle, by camminginterengagement between the inner end of the magazine and cooperativemeans carried by the barrel.

Suitable trigger mechanism is provided for retaining the barrel ininoperative or rearward position and for releasing the barrel forforward movement and firing when the trigger mechanism is manuallyactuated. The trigger mechanism is conventional and may assume any ofvarious forms including, if desired, suitable safety lock means wellknown in the art by which actuation of the trigger is prevented untilthe safety lock is moved to tiring position. Since the present inventionis not directed to the details of a trigger mechanism, such mechanism isherein shown and described in stylized form only in order not to detractby complexity from an understanding of the present invention proper. Theweapon is adapted for either semiautomatic or full automatic operation.

A principal object of the invention is therefore to disclose a novelweapon for operation by compressed gas.

Another object is to disclose a gas operated weapon constituting animprovement in certain respects over my earlier invention shown inUnited States Patent No. 2,688,321.

A further object is to disclose a gas operated Weapon including meansforming a variable volume compression chamber in periodic communicationwith the interior of av reciprocable barrel.

Another object is to provide, in a gas operated weapon magazine meansfor holding a plurality of projectiles and for releasing'one suchprojectile for ring at the proper point in the cycle of operation.

Patented Dec. 31, 1957 Still another object is to provide in a weaponhaving the above characteristics, resilient cumulator means by which tomaintain propelling gas pressure at a relatively high value throughoutthe travel of a projectile through the barrel,

These and other and allied objects and purposes will be understood froma study of the following description of a preferred embodiment of theinvention taken in connection with the accompanying drawings in which:

Fig. l is a longitudinal sectional view of a gas operated pistolembodying the present invention.

Fig. 2 is a fragmentary sectional view, on an enlarged scale, showingthe rear portion of the barrel and the front portion of the feedingmagazine therein, together with associated parts, the weapon beingcocked` Fig. 3 is a sectional view similar to Fig. 2 but showing theparts after the trigger has been pulled, the barrel has moved forwardlyand a projectile has been released from the feeding magazine and hasmoved partially through the barrel.

Fig. 4 is a sectional view similar to Figs. 2 and 3 but showing theparts at a later point in the cycle of operation with the barrel, underthe force of the recoil spring, commencing its rearward movement backtoward cocked position.

Fig. 5 is a fragmentary sectional View on a larger scale than that ofFigs. 2, 3 and 4 and showing the projectile entering the forward sectionof the barrel, the parts being in their positions a moment earlier thanthat shown in Fig. 3. f

Referring now in detail to the drawing and first to Figs. l and 2thereof, the weapon there shown includes a housing frame indicatedgenerally at lll provided with a forwardly projecting barrel supportsleeve 12 securely lixed to the front end portion 14 of the frame ll) asby transverse drift pin i3. Conventional sighting means are providedincluding rear sight l5 and front sight 16. Formed within frame l@ is alongitudinal bore 18 and barrel support means are provided within thebore 18. The barrel support means are here shown as including a rearbushing indicated generally at Ztl and a front bushing indicatedgenerally at 22. The bushings are provided with coaxial longitudinalbores therethrough indicated at 24 and 26 respectively. The rear bushing2t) includes means hermetically sealing with the internal wall of thebore 18 such as an O-ring 28, and the' rear bushing remains stationaryrelative to the frame 10 when the parts are assembled, being in abuttingrelation with the shoulder 30 of the frame. Except for convenience inassembly of the parts, rear bushing 2i) could be made integral withframe 10. Rearwardly of the shoulder 3@ the bushing 2li includes aportion of reduced diameter 3l.

The front bushing 22 includes means hermetically ysealing with the wallof the bore 18 such as -O-riug 32, and

is arranged Ito be longitudinally movable within the bore 18 of theframe relative to the rear bushing 2l?. The front bushing also includesa forwardly extending, preferably integral sleeve 34 of reduceddiameter. Resilient means are provided for urging the front bushing 22rearwardly relative to the frame 10, and such means are here shown asincluding a helical spring 36 bearing at its front end against Athe rearannular end 37 of the barrel support sleeve l2 and bearing at its rearend against the enlarged portion of the bushing 22.

The pistol includes a barrel indicated generally at 40, the barrel beinglongitudinally movable or reciprocable relative to the frame 1t) and itsforward extension or barrel support sleeve 12. The forward portion ofthe barrel is slidably carried by the barrel` support sleeve 12 and thebarrel is supported rearwardly by the coaxial bores 24 and 26 within thebushings 20 and 22 previously referred to. The outer cylindrical surfaceof the barrel 3 is provided with means hermetically sealing with thebore 24 of the rear bushing 20, these means being here shown as anO-ring 42. Rearwardly of this O-ring is a second hermetic seal betweenthe rear bushing `and barrel indicated at 44 and also consisting `of anO-ring or equivalent sealing device. The front .bushing 22 is providedwith means hcrnietically sealing with the barrel in the 4form of O-ring46. Forwardly of the front bushing 22 the barrel includes an annularring or collar 48 received in a recessed groove in the outer surface ofthe barrel and extending outwardly beyond the groove, and the frontbushing 22 is in abutting contact with the collar 48 from the rear bymeans of sleeve 34 when the parts are in the positions seen in Figs. land 2 of the drawings.

Means are provided for resiliently urging the barrel 40 rearwardlyrelative to the frame 10, such means being here shown as including arecoil spring 50 helically disposed about the barrel 40. The recoilspring S0, at its front end, bears against an annular shoulder 52 formedin the barrel support sleeve 12 and at its rear end bears against theoutwardly turned lip S4 of a spacing collar 56. This collar 56 isslidably mounted in the barrel 40 and at its rear end is abuttableagainst the ring 48 extending annularly from the barrel 40.

At the rear end of the barrel 40 there is a barrel extension fixed tothe barrel and of larger diameter. The barrel extension is indicatedgenerally at 60 and includes the enlarged cylindrical member 62 and aforwardly projecting preferably integral tube or sleeve 64 fittingwithin the rear section 65 of barrel 40. It will be noted that the rearsection 65 of the barrel is of considerably larger inside diameter thanthe inside diameter of the forward part of barrel 40 including thefiring tube 66. The barrel extension 60 is fixed to the rear section ofthe barrel 40 and could be formed integrally therewith if desired.`

A suitable trigger assembly is included in the present weapon and mayassume any of many forms well known in the art. Illustratively, thetrigger assembly may include the trigger proper mounted for pivotalrotation on the frame about the pin 72. The trigger is provided with arearwardly projecting arm 74 which, at its rear end, abuts upwardlyagainst an arm 76 of a linkage member indicated generally at 78pivotally mounted on the frame for rotation about the axis 80. Thelinkage member 78 includes a rearwardly extending arm 82 terminating inan upwardly extending sear member 84 which, when the weapon is cocked,abuts the annular front surface of the enlarged portion 62 of the barrelextension 60. The trigger linkage mechanism herein typified includesresilient spring members 86 and 88 urging the parts ofthe triggerlinkage into the positions seen in Figs. 1 and 2.

Means are provided for supplying pressure gas to propel a projectilethrough the barrel 40 during tiring. Such means are here shown asincluding a container `ot compressed gas indicated generally at 90 andhoused within a suitable recess formed in the grip portion 92 of thepistol. The pressure gas container 90 may be replaced when desired byremoval of a suitable closure member indicated generally at 94 whichnormally retains the gas container 90 in the position shown. Apassageway indicated generally at 96 extends between the gas container90 and the bore 18 formed in the frame 10, and the passageway 96terminates upwardly at a port or orifice 98 located just forwardly ofthe front annular face 99 of the rear bushing 20. The passageway 96, atits lower end, is provided with a suitable piercing member 100 adaptedto perforate the upper end wall of the pressure gas container 90 whensuch container is inserted into the housing recess formed in the grip 92and the retainer plug means 94 is tightened thereon.

Means .are .provided for supplying projectiles or pellets intothe rearportion of the barrel of the present weapon. In .the presentillustrative embodiment of the invention such loading or feeding meansinclude an elongated tube indicated generally at which is threadedlyconnected at 112 with the rear portion of the frame, being assembledtherein from the front of the frame. The tube 110 includes an enlargedllange 114 abutting a shoulder formed within the frame of the weapon andforwardly of the ange 114 the tubular member 10 is of a smaller diameteras indicated at 116 and lits within sleeve 64 of barrel extension 60.The front end portion of the tube 116 is provided with a plurality ofvforwardly projecting resilient arms 11S (see Fig. 5) separated bylongitudinal slits 120 therebetween. The arms 118 are resilient and tend`to move outwardly from the center of the tube 116. Toward their frontend the arms 118 incline outwardly to offset portions 122 and at theextreme front end the arms incline inwardly and terminate in directedfingers 124.

A number of projectiles 126 may be inserted and carried within thetubular member 110 in tandem, there being six such `projectiles shown inFig. l. Resilient means :are .provided for urging the projectiles 126forwardly .within the `tube and into abutment against the inturnedfingers 124 of the tube. These resilient means include a relatively weakspring member 130 extending longitudinally `within a sleeve 132, and thesleeve 132 terminates at its rear end in a loading cap 134. The sleeve`and cap .are threadedly connected at 136 to the rear end ot the loadingtube 110. The forward end of the spring `130 abuts a follower tip 14()which in turn is in abutting .contact with the rearmost one oftheprojectiles 126 .and .continuously urges the train of projectilesforwardly when the parts are assembled. The cap 134 may be desirablyknurled at its outer surface to facilitate manual removal of it and itsintegral sleeve 132 containing the spring 130, and when so removedadditional pellets or projectiles may be introduced through the thenopen rear .end of the loading tube 110. Thus the parts just describedconstitute a spring loaded magazine for continuously supplyingprojectiles to the forward end of the tube 116, at which point theprojectiles are restrained from further forward movement by the inturnedlingers 124 until the appropriate moment in the cycle of operation ofthe weapon as will be described in detail here. inafter.

The barrel 40 is of virtually uniform outside diameter throughout Aitslength; the forward section of the barrel has an inner diameter 66throughout the tiring tube proper, while the rear section of the barrelhas an inner diameter 144 :considerably greater than that of the forwardsection. As best appears in Fig. 5, the two sections are connected by aninternal rearwardly directed inclined annular shoulder 146 smoothlyjoining the two inner bores of different diameter. Adjacent the inclined annular shoulder 146 the rear section of the barrel 40 Aincludeson or more ports 148 through the wall `ot the barrel. As will be laterunderstood, these ports 148 periodically admit `pressure gas fromoutside the barrel into the ,interior of the rear section thereof, thepressure gas constituting the `propellant for the projectile 126.

The .cycle of operation of the present weapon will be best understood byconsidering Figs. 2, 3 and 4 showing the parts in their respectivepositions at successive stages in `the c ycle. It may be noted at thispoint that the fragmentar-y view in Fig. 5 shows the parts a momentearlier than that shown in Fig. 3. With reference first to Fig. 2,pressure gas is admitted into the chamber 102 through the passageway 96and the inlet port 98. The pressure within chamber 1 02 is exertedforwardly against the annular face 104 -of the front bushing member 22and its force is .thereby applied to the barrel by reason of theabutting contact between the front `annular shoulder of .the .sleeve2.6.01 bushing 22 and the ring collar 48 carried by the barrel. Thisforce resulting from the gas pressure fin chamber 102 is more thansutiicient to overcome the rearward force upon the bushing 22 caused bycumulator spring 36 and also the rearward force exerted upon the ringcollar 48 through the spacer member 56 by the recoil spring 50. Thus theresultant force on the barrel is forwardly, and the barrel is restrainedfrom actual forward movement by abutment of the sear 84 against theforward annular shoulder of the barrel extension 60. It will be seenthat pressure gas existing within the chamber 102 is prevented fromescaping therefrom by reason of the hermetic sealing members or O- rings32, 46, 28 and 42.

At this time forward movement of the projectiles 126 under the influenceof the weak follower spring 130 is prevented because the fingers 124 ofresilient arms 118 are cammed into their inner positions blocking thefront'projectile 126 by reason of the caming action of the internalannular shoulder 146 against the offset portions 122 of the arms.

The parts move into the position seen in Fig. and thence into theposition seen in Fig. 3 when the trigger is actuated and the sear 84 isdrawn downwardly by such actuation. With reference iirst to Fig. 5,forward movement of the barrel 40 relative to the rear bushing 20permits the oifset portions 122 of the arms 118 to spring outwardlybecause of ktheir sliding or camming engagement with the annularshoulder 146 on the interior of the barrel. arms 118 and their lingers124 releases the front projectile 126 and permits forward movement ofsuch projectile. At the same time the forward movement of the barrelpermits pressure gas to enter the ports 148 in the barrel since theO-n'ng 42 is moved forwardly out of its former sealing engagement withthe inner bore 24 of the rear bushing 20. Sincer the front projectile126 is no longer restrained by the lingers 124, and since gas pressureexists behind it, the projectile moves forward into the position seen inFig. 5, where it is just entering the tube 66 of the front section ofthe barrel 40. The strength of the spring 130 urging the projectiles 126forwardly is relatively weak and hence the second projectile is notimmediately moved forwardly when gas pressure behind the firstprojectile moves the latter into its position of Fig. 5.

Continued forward movement of the barrel 40 from the position of Fig. 5brings the parts into the position seen in Fig. 3. The forwardlyextending arms 11S of the tubular member 116 are now cammed back intotheir inner positions by reason of slidably contacting the forwardlyextending sleeve 64 of the barrel extension 60. Thus the projectiles 126which are still within the tube 116 are to a certain degree restrainedfrom forward movement under the influence of the magazine spring 130 byreason of frictional engagement between the cylindrical side wall 127 ofthe projectile and the inner surfaces of the resilient arms 118. Theforward movement of the barrel has by this moment also completelyuncovered the ports 148 formed in the side wall of the barrel, thuspermitting free entrance into the barrel of pressure gas within thechamber 102. The front bushing member 22, further compresses cumulatorspring 36, under the force of the gas pressure within the chamber 102exerted against the rearward annular face 104 of the bushing member,since the annular collar ring 48 moves forward with the barrel. Therecoil spring 50 is also compressed by the forward movement of thebarrel.

A moment following the point in the cycle shown in Fig. 3 the pressureof the gas within the chamber 102 commences to decrease. This is becauseof the fact that the gas within chamber 102 is being permitted to escapethrough the ports 148 formed in the barrel, and gas is being resuppliedto the chamber 102 from the container 90 only through the relativelysmall orifice or port 93. It may be here noted that no gas escapesrearwardly, since O-ring 117 engaging tube 116 prevents this and thethreaded engagement 136 of cap 134 is virtually gas This outwardmovement of the 4, as soon as gas pressure within the chamber 102suffi-l ciently decreases, the front bushing 22 is forced rearwardly bythe cumulator spring 36 to decrease the volume of the chamber 102 andthus to tend to maintain the gas pressure high within that chamber and,via ports 148, also within the barrel. In Fig. 4 this situation is shownand it is especially to be observed that the sleeve portion 26 of thefront bushing 22 is no longer in abutting contact with the ring collar`48 carried by the barrel. Nevertheless, the barrel 40 does notimmediately move rearwardly even though the force of the recoil spring50 urges it rearwardly. This is for the reason that the momentum of theforwardly moving barrel 40 and barrel extension 60, in view of the highspeed at which the actions described herein take place, is sufficient tomomentarily resist the rearward forceof the recoil spring 50. It will beseen, however, from` a consideration of Fig. 4 that eventually therecoil spring 50 will absorb the force resulting from the momentum ofthe forward movement of the barrel and barrel extension, and will returnthose parts to their rear positions. This is accomplished in the presentmechanism by reason of the fact that only a small gas pressure can buildup withinchamber 102 so long as the barrel 40 is substantially forwardof its rearinost position and hence permits escape of pressure gas fromchamber 102 through the ports 148 and thence outwardly through thebarrel 40. The last portion of thek rearward movement of the barrel 40serves to reestablish the hermetic seal existing between the sealingmeans 42 and the inner bore 24 of the rear bushing member 20, and theparts then come to rest in thc position of Fig. 2. It will be understoodthat during the rearward movement of the barrel from the position ot'Fig. 4 back to the position of Fig. 2, the arms 11i? of the feedingmagazine are permitted to momentarily spring outwardly (when the partspass through the position seen in Fig. 5) and thus to permit forwardmovement of the front projectile 126 into abutting contact with theinturned fingers 124 of the resilient arms, in position to be next red.e

Accordingly, it will be seen that there is here provided a gas-operatedweapon for ring projectiles through a barrel and including resilientlybiased pressure cumulator means for maintaining gas pressure at a highvaluc throughout the movement of the projectile in the barrel andmagazine feed means for introducing a projectile to tiring position atthe appropriate point in the cycle. lt will be readily understood thatthe invention may be ap plied to a weapon other than a pistol ifdesired. lt will be further understood that auxiliary devices andequipment normally associated with a hand-operated weapon may be changedsubstantially from the illustrative forms typically shown herein withoutdeparting from the essence of the present invention as defined in theappended claims.

Those skilled in the art will recognize that the .above actions takeplace at high speed. T e cyclic rate of re of the present weapon issomewhat variable depending upon the gas pressure within container 90,the physical constants of the component parts and other factors. Thecyclic rate ranges between about two hundred and four hundred rounds perminute under normal conditions.

I claim:

l. In a gas operated gun: a frame provided with a longitudinal chambertherein and a forwardly projecting tubular extension aligned with saidchamber; a rear bushing in said chamber hermetically sealed with theframe and provided with a cylindrical bore therethrough and a forwardlydirected annular face; a front bushing slidable within the frame andhermetically sealing therewith and provided with a cylindrical boretherethrough in coaxial alignment with said first named bore and havinga rearwardly 4directed annular face; a 4barrel rslida'bly mounted forlongitudinal movement -in said bores 'and hermetically sealingtherewith; resilient means urging saidfront bushing rearwardly ytowardsaid rear bushing; the `outer surface 'of the barrel, the inner wall ofthe frame rand said `annular faces forming a variable volume compressionchamber; means carried by the barrelfor positively limiting forwardmovement of the front bushing relative 'to the lbarrel; means for'introducing gas under pressure into said compression chamber; saidbarrel including a front section and a `rear section, the rear sectionhaving a 'larger inside diameter than the front section and mergingtherewith in a rearwardly directed inclined annular shoulder, said rearsection being provided with a port through the wall of the barrelyadjacent said shoulder; a loading tube lfixed relative to `the frameand projecting forwardly into and slidable within said rear sectionadapted to hold a plurality of projectiles, `the tube includingforwardly projecting fingers having inturned tips, the fingers beingresiliently biased outwardly and being cammed inwardly by slidingengagement with said shoulder; and resilient means urging the barrelrearwardly relative to the frame.

2. ln a gas operated pistol: a frame having a forwardly projectingsupport bearing; a barrel supported by said frame and bearing andlongitudinally movable relative thereto between forward and rearpositions, -said barrel having a front section provided with alongitudinal bore therein and a rear section provided with a second bores coaxial with and of larger vdiameter than the first-named bore, saidsections being joined by an internal annular inclined shoulder, thebarrel being provided with a gas inlet port formed in the wall of therear section; means for supplying pressure gas to the outer end of saidport when the barrel is in its forward position; means urging the barrelforwardly relative to the frame; a feeding tube selectively stationarilyattachable to the frame and including a front portion projecting intoVand sealing with the rear section of the barrel, said front portionincluding fingers resiliently biased outwardly and in slidable contactwith the inner wall of said first-named bore when the barrel is in rearposition, the tip portions of the `fingers being directed inwardly;means for latching the barrel in rear position; and selectively operablemeans for releasing said latching means.

3. In a gas operated weapon, in combination: a tubular barrel having afront section and a rear section, the rear section having a largerinside diameter than the front section and merging therewith in aninclined internal annular shoulder, the rear section being providedywith a port through its -wall adjacent said shoulder; a rear bushinghaving a forwardly directed annular face and a cylindrical borehermetically and slidably encircling the barrel; a front bushing `havinga rearwardly directed annular face and a cylindrical bore lhermeticallyand slidably encircling the barrel; housing means hermetically Vsealing`with and encircling said bushings and forming therewith and with thebarrel a compression chamber, the housing means being provided with aninlet port communicating with the chamber for supplying pressure Igasthereto; and a feeding tube Xed relative to the housing means 4andprojecting forwardly into the rear section of the barrel, the feedingtube being adapted to contain a plurality of projectiles and resilientmeans for urging the projectiles forwardly, the feeding tube `includingoutwardly biased, inwardly directed movable retaining means cooperatingwith the iuternal `shoulder ofthe barrel for holding projectiles in thetube when the barrel is in rearmost position relative tothe housingmeans.

4. In a gas operated object propelling mechanism: a tubular barrelhaving a front object emitting end and a rear end and a radiallydisposed gas inlet port intermediate the `ends; a feeder magazineextending forwardly into the barrel from the rear end thereof andlongitudinally slidable therein, the magazine being adapted to contain aplurality of propellable objects and including means for urging saidobjects forwardly and forwardly disposed outwardly biased, radiallymovable means for releasing an object upon outward movement thereof; thebarrel being formed Awith 'an enlargement therein forwardly of said portfor permitting outward movement of said outwardly biased means uponforward longitudinal movement of the barrel relative to the magazine;and means for introducing pres sure gas through said port rearwardly ofthe frontmost object upon outward movement of said outwardly biasedll'leallS.

References Cited in the le of this patent UNITED STATES PATENTS2,048,061 Donato July 21, 1936 2,673,557 Shermanret al Mar. 30, 19542,688,321 Martin Sept. 7, 1954l

